AYESHA RASCOE, HOST:
NASA tried to launch its new moon rocket twice last week, and each time, technical glitches prevented this historic launch from happening. Now it looks like the space vehicle may need repairs before the next attempt, which means more delays. NPR's Nell Greenfieldboyce has been at the Kennedy Space Center all week, and she joins us now. Good morning.
NELL GREENFIELDBOYCE, BYLINE: Hey there.
RASCOE: So what went wrong?
GREENFIELDBOYCE: Basically, yesterday, they were trying to fill up a fuel tank. And that tank is supposed to hold about half a million gallons of super cold liquid hydrogen. But as they were filling it up, they basically detected a hydrogen leak from a fuel line and its connection, and that's a fire hazard. So they tried several times to fix it by stopping and restarting the fill-up process, but that didn't work. It was just a large, persistent leak.
RASCOE: And they've seen hydrogen leaks before, like in the first launch attempt, right?
GREENFIELDBOYCE: Oh, yeah. And in dress rehearsals for launches, too. NASA mission controllers were able to resolve the leak that happened during the first launch attempt, and that attempt was eventually called off because of another glitch, a separate thing, a faulty engine temperature sensor. And, you know, they tried again to launch. And this time, the hydrogen leak was bigger. It was in a different spot, and it just wouldn't go away.
RASCOE: I mean, it sounds like what happens with, like, your car or your van or something. You got that weird leak. Do they have any idea what caused it?
GREENFIELDBOYCE: Well, one possibility is that an operator sent the wrong commands to a valve they shouldn't have that resulted in a sort of overpressure situation. It was corrected almost instantly. But officials say this might have damaged the fuel line seal or something like that. Mike Sarafin is NASA's Artemis mission manager. He told reporters during a briefing that, really, it's too soon to know.
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MIKE SARAFIN: We're just going to have to take time to look through it. We're going to look through the data, and we will go back and reassess exactly why this inadvertent command happened.
GREENFIELDBOYCE: They're also going to inspect the trouble spot on the rocket and see if it needs any fixes, like replacing parts.
RASCOE: So this rocket's technology was based on the old space shuttles, which flew for 30 years. Is it surprising that they're having such trouble just fueling it up?
GREENFIELDBOYCE: It's not like your car, is it? Hydrogen is good rocket fuel, but it's the smallest, lightest element, and it's just notoriously hard to contain. One NASA official, Jim Free, told reporters that the space shuttles had lots of problems with hydrogen leaks.
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JIM FREE: The summer of 1990 was the summer of hydrogen, where shuttle had been launching for nine years. And they spent a whole summer chasing hydrogen leaks. So I'm not saying that's an excuse. That's just a fact.
GREENFIELDBOYCE: Some rocket designers are moving away from hydrogen. Like, the company SpaceX is building a massive rocket called Starship, and it's going to use methane.
RASCOE: So let's say there have to be some fixes around this fuel line. How long is that going to take?
GREENFIELDBOYCE: It really depends. It depends on whether they can do the fixes at the launch pad, or if they have to roll the whole big rocket back to its hangar. If they can do it at the pad, they might try again later this month. But if they have to roll back, we're looking more like mid-October.
RASCOE: That's NPR's Nell Greenfieldboyce in Melbourne, Fla. Thank you so much for joining us.
GREENFIELDBOYCE: Thank you. Transcript provided by NPR, Copyright NPR.
